BERLIN (Reuters) - Germany’s DIHK Chambers of Commerce and Industry said on Monday the escalating trade dispute with the United States is causing huge uncertainty among German exporters that are also indirectly burdened by U.S. sanctions against Iran and Russia.

U.S. President Donald Trump backed out of a joint communique agreed by Group of Seven leaders in Canada at the weekend that mentioned the need for “free, fair and mutually beneficial” trade and the importance of fighting protectionism.

“The trade dispute is currently leading to considerable uncertainty among German companies doing business abroad,” Volker Treier, foreign trade chief at the DIHK, told Reuters.

“The G7 summit fiasco showed how deep the political rift is and what dangers could still lurk ahead,” Treier added.

The U.S. import tariffs on steel and aluminium and possible additional duties on automobile imports clearly violate international rules, Treier said.

As Europe’s biggest exporter to the United States and with more than one million German jobs at stake, Germany is desperate to avoid an EU-U.S. trade war.

Treier said that unilaterally imposed U.S. sanctions against Russia and Iran were also increasingly putting a burden on the German economy.

Due to extra-territorial effects of the U.S. sanctions, many German companies are currently winding down operations abroad and stopping efforts to develop new business, he said.

“These irritations are already noticeable in trade with the U.S.,” Treier said.

German exports to the United States, its biggest export market after the bloc of European Union countries, have already declined slightly since the beginning of the year.

“This means that the DIHK export forecast of more than 5 percent German export growth in the United States is already more than questionable,” Treier said.

“Companies need reliability for their foreign business. That is why it is so important for the EU to be fully committed to strengthening the WTO and global rules.”